This invention relates to breakaway coupling for use with gasoline dispensing equipment.
Emergency breakaway valves came about due to equipment damage that occurred when a customer drove off with the gasoline dispensing nozzle in his tank. The original breakaway couplings were fairly simple in design. However, eventually, vapor recovery was mandated, and emergency breakaway couplings compatible with various vapor recovery systems were needed.
Vapor recovery systems incorporate the use of two hoses or flow paths: one for fuel delivery and the other for vapor return; either as side-by-side flow paths or in coax configurations. Thus, emergency breakaway valves were developed to be used with these different systems and hoses. The emergency breakaway valves that were developed for use with coax vapor hoses require that fuel and vapor paths be separated. The valve is constructed such that the vapor path is contained by the inner hose and the fuel path is defined by the outer hose. When this emergency breakaway valve separates, the fuel valve moves relative to the vapor passage cylinder during closing. In current instances contaminants would build up on or behind the primary fuel to vapor o-ring, which could potentially create a wedging action and cause the valve to close slowly or prevent closure of the check valves. Either of these conditions allows excess fuel to spill and create a potential hazard.